<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Null.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Filter_Null implements Zend_Filter_Interface {
	const BOOLEAN = 1;
	const INTEGER = 2;
	const EMPTY_ARRAY = 4;
	const STRING = 8;
	const ZERO = 16;
	const ALL = 31;
	
	protected $_constants = array (self::BOOLEAN => 'boolean', self::INTEGER => 'integer', self::EMPTY_ARRAY => 'array', self::STRING => 'string', self::ZERO => 'zero', self::ALL => 'all' );
	
	/**
	 * Internal type to detect
	 *
	 * @var integer
	 */
	protected $_type = self::ALL;
	
	/**
	 * Constructor
	 *
	 * @param string|array|Zend_Config $options OPTIONAL
	 */
	public function __construct($options = null) {
		if ($options instanceof Zend_Config) {
			$options = $options->toArray ();
		} else if (! is_array ( $options )) {
			$options = func_get_args ();
			$temp = array ();
			if (! empty ( $options )) {
				$temp = array_shift ( $options );
			}
			$options = $temp;
		} else if (is_array ( $options ) && array_key_exists ( 'type', $options )) {
			$options = $options ['type'];
		}
		
		if (! empty ( $options )) {
			$this->setType ( $options );
		}
	}
	
	/**
	 * Returns the set null types
	 *
	 * @return array
	 */
	public function getType() {
		return $this->_type;
	}
	
	/**
	 * Set the null types
	 *
	 * @param  integer|array $type
	 * @throws Zend_Filter_Exception
	 * @return Zend_Filter_Null
	 */
	public function setType($type = null) {
		if (is_array ( $type )) {
			$detected = 0;
			foreach ( $type as $value ) {
				if (is_int ( $value )) {
					$detected += $value;
				} else if (in_array ( $value, $this->_constants )) {
					$detected += array_search ( $value, $this->_constants );
				}
			}
			
			$type = $detected;
		} else if (is_string ( $type )) {
			if (in_array ( $type, $this->_constants )) {
				$type = array_search ( $type, $this->_constants );
			}
		}
		
		if (! is_int ( $type ) || ($type < 0) || ($type > self::ALL)) {
			require_once 'Zend/Filter/Exception.php';
			throw new Zend_Filter_Exception ( 'Unknown type' );
		}
		
		$this->_type = $type;
		return $this;
	}
	
	/**
	 * Defined by Zend_Filter_Interface
	 *
	 * Returns null representation of $value, if value is empty and matches
	 * types that should be considered null.
	 *
	 * @param  string $value
	 * @return string
	 */
	public function filter($value) {
		$type = $this->getType ();
		
		// STRING ZERO ('0')
		if ($type >= self::ZERO) {
			$type -= self::ZERO;
			if (is_string ( $value ) && ($value == '0')) {
				return null;
			}
		}
		
		// STRING ('')
		if ($type >= self::STRING) {
			$type -= self::STRING;
			if (is_string ( $value ) && ($value == '')) {
				return null;
			}
		}
		
		// EMPTY_ARRAY (array())
		if ($type >= self::EMPTY_ARRAY) {
			$type -= self::EMPTY_ARRAY;
			if (is_array ( $value ) && ($value == array ())) {
				return null;
			}
		}
		
		// INTEGER (0)
		if ($type >= self::INTEGER) {
			$type -= self::INTEGER;
			if (is_int ( $value ) && ($value == 0)) {
				return null;
			}
		}
		
		// BOOLEAN (false)
		if ($type >= self::BOOLEAN) {
			$type -= self::BOOLEAN;
			if (is_bool ( $value ) && ($value == false)) {
				return null;
			}
		}
		
		return $value;
	}
}
